Starters for automobile vehicles are mostly actuated by a rotary switch which is usually combined with a barrel-type lock controlling an anti-theft device, such as a bolt member which locks the steering column.
It is very important to arrange that the starter cannot be actuated accidentally while the engine of the vehicle is running, since the starter mechanism might be damaged thereby. It is known to provide, for this purpose, the switch or the lock combined therewith, with a device which precludes bringing the switch to the starting position before passing through a position in which the electric power supply to the engine is cut off, which stops the engine if it was running. Such devices are known, some of which are purely electrical, some purely mechanical and others electro-mechanical.
Mechanical devices have been proposed which comprise a member slidable between two positions in a recess and blocking the switch in one direction of rotation in one of its two positions so that the slidable member must be returned to the other position before it is possible to pass to the starting position (see, for example, French Pat. No. 1,547,973 and German Pat. No. 1,776,131).
These known devices have many parts of precise dimensions and fitting and are consequently expensive, difficult to assemble and subject to wear.
An elastically yieldable lug has also been proposed (see French Pat. No. 2,127,164) which is axially guided by a helical ramp which brings the lug in front of an abutment if the switch is not first moved to the "off" position. This device is also rather complicated to assemble and the strength of the abutment in rotation is not always sufficient in that it is ensured by a sliding member returned by a spring.
An object of this invention is to avoid the drawbacks of known mechanical safety devices and to provide an extremely simple novel device which allows wide tolerances and has very high strength.
According to the present invention, there is provided a safety device for a rotary starter switch for an automobile vehicle, of the type comprising a non-rotatable part and a part rotatable with respect to the non-rotatable part about the axis of revolution, the safety device comprising elastically yieldable means connected to one of the parts and a profile integral with the other part and constraining said elastically yieldable means to move through two different paths depending on the direction of rotation, one of which paths has an anti-return abutment, wherein said elastically yieldable means comprise a spring blade so disposed as to be cooperative by its edge with said anti-return abutment.
The use of a spring blade permits a very simple assembly with wide tolerances having regard to the width of the blade. Moreover, the abutment of the blade by its edge provides exceptional strength.
The blade may be connected to rotate with the rotatable part or prevented from rotating relative to the fixed part. In the latter case, the blade may be integral with the fixed part or, by way of a modification, integral with a member which is movable with respect to the fixed part, for example integral with a locking bolt member.
The use of a spring blade also ensures various additional indexing functions.